Basic implementation of GeofencingManager class.

content/browser/geofencing/geofencing_provider.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_BROWSER_GEOFENCING_GEOFENCING_PROVIDER_H_
+#define CONTENT_BROWSER_GEOFENCING_GEOFENCING_PROVIDER_H_
+
+#include "base/callback_forward.h"
+#include "content/common/geofencing_status.h"
+
+namespace blink {
+struct WebCircularGeofencingRegion;
+};
+
+namespace content {
+
+class GeofencingProvider {
+ public:
+  // Callback that gets called on completion of registering a new region. The
+  // status indicates success or failure, and in case of success, an id to use
+  // to later unregister the region is passed as |registration_id|. If
+  // registration failed, the value of |registration_id| is undefined.

[Michael van Ouwerkerk, 2014/10/06 16:43:42]

I think it would be clearer to set registration_id to a known constant value on
failure.

[Marijn Kruisselbrink, 2014/10/06 19:14:11]

Changed the comment to document what value providers should set registration_id
to on failure, although it's probably still better for GeofencingManager to not
rely on this.

+  typedef base::Callback<void(GeofencingStatus, int registration_id)>
+      RegisterCallback;
+
+  virtual ~GeofencingProvider() {}
+
+  // Called by |GeofencingManager| to register a new fence. GeofencingManager is
+  // responsible for handling things like duplicate regions, so platform
+  // specific implementations shouldn't have to worry about things like that.
+  // Also GeofencingManager should be making sure the total number of geofences

[Michael van Ouwerkerk, 2014/10/06 16:43:42]

How would the caller know what the limit of the platform specific provider is?
You'd need to  expose that as part of the provider API, and it requires the
provider to know. An alternative would be to allow for a 'limit reached'
failure.

[Marijn Kruisselbrink, 2014/10/06 19:14:11]

Yes, that's something the provider API will have to expose. Until I actually get
to implementing support for this in the manager it doesn't really make sense to
expose that here though, and instead I imagine providers will indeed return some
kind of limit reached failure (which without special support in the manager will
just get passed through to the website, which isn't very helpful as long as this
is a global limit).

+  // that is registered with the platform specific provider does not exceed the
+  // number of regions supported by the platform, although that isn't
+  // implemented yet.
+  virtual void RegisterRegion(const blink::WebCircularGeofencingRegion& region,
+                              const RegisterCallback& callback) = 0;
+
+  // Called by |GeofencingManager| to unregister an existing registration. Will
+  // only be called once for each registration.
+  virtual void UnregisterRegion(int registration_id) = 0;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_GEOFENCING_GEOFENCING_PROVIDER_H_